Okay first off; so JOIN + LATERAL VIEW together isn't working so I moved my JOIN into a subquery and that makes the query work properly
However when I added a MAPJOIN hint for the JOIN in the subquery it will also stop doing the reducer for the main query! This only happens when there's a LATERAL VIEW in there though, if I remove the LATERAL VIEW then the main query still get's a reducer to do grouping Here's a gist: https://gist.github.com/2499436 Containing the queries and a PHP script which you can run to execute the test case; - setup a database called hive_mapjoin - setup tables - load some test data - do the selects You'll need the https://github.com/rcongiu/Hive-JSON-Serde/downloads json-serde-1.1-jar-with-dependencies.jar with it though and change the path ;) Not sure if this is a bug or me doing something that just isn’t supposed to be working, Thanks Ruben
